Apparatus for manufacturing glass bottles

ABSTRACT

An apparatus for manufacturing glass bottles is disclosed which includes consecutively delivering gobs of molten glass into a blank mold, forming each gob into a parison, transferring the parisons alternately into at least two sets of blow molds, allowing said parisons to reheat, and expanding the parisons in the blow molds. The sets of blow molds recipricate along a substantially vertical path. A first position where the parisons are alternately received by the blow molds and blown containers removed is located on the vertical path. The parisons are expanded and cooled in the blow molds by blowing them out or by applying a vacuum, or a combination of those means at a second position on the vertical path. The apparatus is an improvement to forming sections of the well known Hartford type I.S. machine.

This application is a continuation-in-part of my pending applicationSer. No. 906,048 filed May 15, 1978, now abandoned.

BACKGROUND OF THE INVENTION

In the glass industry today the most common glass containermanufacturing machine is the Hartford type "I.S." machine. It isestimated that in the United States alone, there are over six thousand"I.S." sections in daily operation. This machine is described in IngleU.S. Pat. Nos. 1,843,160 and 1,911,119.

A basic "I.S." eight-section machine today costs several hundredthousand dollars. An important advantage of the present invention isthat it is applicable to the existing production facilities of theindustry.

In the original disclosure of the I.S. machine, the machine was intendedto make glass containers by the well-known "blow and blow" process.Subsequently, Rowe U.S. Pat. No. 2,289,046 disclosed the "62" processwhich could be applied to the basic machine to enable it to makecontainers by the "press and blow" process which is the preferred methodof manufacturing wide mouth ware or jars. This development enabled theglass industry to use one machine for all types of ware instead ofhaving a "narrow neck" machine like the Owens or Lynch machines formaking bottles and a "wide-mouth" machine like the Miller machine formaking jars.

The present invention relates primarily to the manufacture of glasscontainers on the I.S. machine by the well-known "blow and blow" processalthough there are some instances where it can also be used to advantagein the manufacture of glass containers in the I.S. machine using the"press and blow" process. Although minor variations to the process existin the industry, the following discussion describes generally the stepswhich are most common. A gob of molten glass is delivered into aninverted blank mold at the bottom of which is situated a neck ring and aplunger. The gob is blown down into the cavity with compressed air toinsure the complete filling of the neck ring. The plunger is thenreceded, a baffle plate closes the top end of the blank cavity, andcompressed air is applied through the orifice created by the withdrawalof the plunger, thereby expanding the glass into intimate contact withthe interior surfaces of the blank mold and baffle plate. Theglass-to-mold contact is continued long enough to create an "enamel"skin on the outer surface of the resulting glass parison.

The baffle plate is then removed and the blank mold is slightlydisengaged from the parison so that the parison is held in a verticalposition supported only by the neck ring. At this time, the parisonstarts to "reheat" which refers to the flow of heat from the interiorglass to the outer surfaces of the parison and to the heat reflectedfrom the interior surface of the blank mold to the outer surface of theparison. The step of reheating the parison plays an important role inimproving the strength of the final glass bottle. Following this, theneck ring and parison are transferred and inverted to the blow moldposition. The blow mold closes around the parison as the neck ringreleases its hold, and the parison becomes supported at the top of theblow mold by a finish ring or bead located just below the finish of theparison. The parison, of course, continues to reheat during its transferto and positioning in the blow mold until the time it is expanded intocontact with the interior wall of the blow mold.

After its suspension in the blow mold, compressed air and/or vacuum areapplied, at the proper time, to expand the parison to the interiorcontours of the blow mold. The cooling contact between the blown glassbottle and the blow mold is maintained until the bottle assumes asufficient degree of rigidity to be capable of standing on its own. Thenthe blow mold is opened and the glass bottle is removed therefrom andtransferred to a cooling plate or conveyor.

As glass bottles have been designed for lighter weights and thinnerwalls, the length of time required to blow and cool the bottle in theblow mold has decreased significantly. Therefore, in order to maintainthe blank side time in the proper relation to the blow side time, it hasbeen necessary to reduce the time available for reheating the parison.

In the ideal production of thin-walled containers, the interval forreheating prior to blowing must exceed a predetermined minimum period oftime in order to insure equalization of temperatures in all zones of theparison and to thus achieve uniform viscosity prior to final expansion.Reheating of the parison walls proceeds from the interior zone towardthe exterior and, therefore, this step cannot be speeded up appreciablyby auxiliary equipment. It also requires more time on containers wherethe parison has been formed by the "blow and blow" process than as thosewhere the parison has been formed by the "press and blow" processbecause, in the former there is no plunger contact to cool the interiorwall of the parison as there is in the latter process.

Many inventors, recognizing the importance of the "reheat" have proposedmeans to increase it. These include Wadman U.S. Pat. No. 2,084,285,Wadman U.S. Pat. No. 2,151,876, Becker U.S. Pat. No. 3,622,304, FosterU.S. Pat. No. 4,009,016 and Zappia U.S. Pat. No. 4,058,388. Because noneof these disclosures is applicable to the basic "I.S." machine they havenot met with commercial acceptance.

It is important to keep the proper relationship between the blank sidetime and the blow side time to maintain a proper amount of reheating forthe parison. In an attempt to improve the reheating time for theparisons additional blow molds have been provided so that the parisonscan have additional reheat time without slowing down the parison formingor bottle forming process. The additional blow molds have been added tothe bottle forming machine in usually one of two ways in the prior art.An additional set of blow molds can be added to one side of the parisonforming equipment so that the parisons can alternately be supplied toeach set of horizontally separated blow molds. (U.S. Pat. No. 3,216,813is one example of this type of prior art system). The additional blowmolds add a great deal of width to the bottle forming machine andrequire an additional parison transfer mechanism to service theadditional blow molds. Such a mechanism requires a complete revamping ofthe forming stations and cannot be used with the standard I.S. machine.

The other prior art solution is to place two sets of blow molds on ahorizontally reciprocating mechanism that alternately moves a blow moldset into position to receive parisons (U.S. Pat. No. 2,151,876 is oneexample of this type of prior art system). Once the first set of blowmolds receives parisons the molds are horizontally translated and thesecond set of blow molds moves into position to receive parisons. Thearrangement allows the parisons to have adequate reheat time while theparisons are being transferred to the blow molds and before the parisonsare blown or expanded in the blow molds. However, the horizontalmovement of the blow molds can cause the parisons to deform or move inthe blow molds. Any such movement of the molten glass can producenon-uniformities in the parison that create non-uniformities in thefinished blown bottle. Also the parison can deform to an extent, duringthe horizontal movement, to cause the parisons to contact the surface ofthe blow molds. Once the parisons contact the surface of the molds heattransfer occurs between the portion of the parison and the mold. Thetransfer disrupts the reheating of the parison in the area where theparison is in contact with the mold and creates a non-uniform reheatingof the parison. The non-uniform reheating of the parison can create weakspots or defects in the finished bottle. The transfer of the parisonsfrom the parison forming molds to the blow molds can also cause theparisons to deform or become off center. The subsequent horizontalmovement of the blow molds will tend to magnify any such defects in theparisons and result in unsatisfactory bottles. Accordingly, the priorart solutions to the reheat problems have proven to be inadequate andnot adaptable to present machines.

A substantial advantage of the present invention is that it is designedto be used with the Hartford type I.S. bottle forming machines. TheHartford type I.S. machine forming section has a width of under two (2)feet and bottle production facilities are designed to take maximumadvantage of this width. The vertically reciprocating blow molds of thepresent invention can be added to the Hartford type I.S. machine withoutincreasing the width of the bottle forming station of the machine. Thus,the present invention can be used to increase production rate in abottle forming facility by adding the invention to standard bottleforming machinery.

SUMMARY OF THE INVENTION

The present invention relates to and provides a novel modification tothe known bottle forming process whereby reheat time is maintained forthinner and lighter bottles, and production speed is increased. Thereheat time itself is maintained or increased by eliminating some or allof the reheat part of the cycle from the blank mold section and placingit in the blow mold section. Sufficient time for reheating and blowingat higher production rates is made available by using a plurality ofblow molds for each blank mold. With this arrangement, one set ofparisons may be reheated and blown in one set of blow molds while, at asecond set of blow molds, blowing of a set of bottles is completed, thebottles are removed and a new set of parisons is delivered. Theplurality of blow molds reciprocate along a substantially vertical pathand into and out of a position where the parisons are alternatelyreceived by the pairs of blow molds. The vertical path falls within theplane of transfer of the parison from the blank mold to the blow molds.The parisons are held in the blow molds for a sufficient period of timeto achieve reheating prior to blowing the parisons into bottles.Reheating the parisons in the blow molds can improve the glassdistribution because of the gravitational centering of the parisons withrespect to the blow molds. This may be necessary if the parisons havebeen forced off-center by the action of the parison transferringmechanism.

Although the invention is described as having two sets of blow molds itshould be noted a greater number of sets of blow molds could be used inthis invention. The additional blow mold sets would be positioned sothat they reciprocate along the vertical path with the other blow moldsets. In this fashion any number of blow molds could be utilized toobtain the desired amount of reheat time. However, for the sake ofexplanation, the invention will be described as having two sets of blowmolds.

It is therefore, an object of the invention to provide a method andapparatus for manufacturing lightweight glass bottles whereby asubstantially increased reheat time is available for promoting thestrength of the bottle.

It is further an object of this invention to provide a method andapparatus for manufacturing lightweight glass bottles whereby theproduction speed and efficiency is increased.

It is still further an object of the present invention to provide amethod and apparatus for manufacturing glass bottles whereby theuniformity of glass distribution is improved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-5 are overall schematic views of a portion of a glass bottlemanufacturing machine illustrating the steps of a preferred method ofthe present invention; and

FIG. 1a is a front and partial sectional view of the reciprocating blowmold apparatus in FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is an improvement in the method of manufacturingnarrow neck glass bottles by the well-known "blow and blow" process.However, it will be apparent to the artisan that the method may also beused with the "press and blow" process with some utility. For detaileddescriptions of typical apparatus and procedures used in the "blow andblow" process, reference may be had to the following U.S. Pat. Nos.:1,911,119; 2,289,046; 2,290,798; 2,309,378; 2,355,036 and 2,702,444. Ofcourse, most of the machinery used with other methods, such as "pressand blow" are also useful with the present invention and references maybe had to such machinery as typically shown in U.S. Pat. Nos. 2,289,046and 3,024,571. For purposes of understanding the present invention,reference will be made to the simplified illustrations in FIGS. 1-5, and1a.

FIGS. 1-5 depict only that portions of the glass container manufacturingapparatus which is most directly concerned with the method of thepresent invention, i.e., a parison-forming unit 10, a transfer mechanism11, and a reciprocating blow mold apparatus 12. FIG. 1a is a front viewof the blow mold apparatus 12 as shown in FIG. 1. The apparatus isintended to replace the standard comparable forming station of existingI.S. machines.

For purposes of illustration, FIG. 1 portrays the point duringmanufacture at which the parisons 15 have already been formed and areready for transfer. The actual methods and the I.S. machines used forforming the parison 15 in the blow and blow process are well-known inthe art and do not constitute a critical part of the present invention.Generally, such parisons 15 are formed by delivering glass charges orgobs to an inverted split blank mold 16 having multiple cavities 16a,and which comprises two mold halves pivotally movable into and out of aparison forming position about a stationary pivot pin 17. The blank mold16 lies superjacent to a split neck ring 18 supported by a neck ringholder 19, both of which are detachably affixed to a support arm 20 forinvert transferring the formed parisons 15 to the blow mold apparatus12. Immediately below the neck ring 18, and in alignment therewith, ismounted a vertically disposed, generally cylindrical housing 25 whichcontains the operating mechanism for counter-blowing the glass chargesinto a pair of parisons 15. In operation, after the glass charges havebeen delivered to the blank mold 16, the mold 16 is closed at the topwith baffles (not shown), and settle blown, by means of compressed airdirected into the mold 16 through the baffles, to assure completemolding of the finish threads in the neck ring 18 and to compact thecharge. During the time the parisons are settle blown, a neck pin orplunger (not shown) is situated within each neck ring 18, but issubsequently retracted to form a small cavity within the compacted glasscharge. Compressed air is counter-blown into the cavity to expand thecharge against the molding surfaces of the blank mold 16 and baffles toform the parisons 15. After formation of the parisons 15, the bafflesare removed and the parisons are ready to be transferred to the blowmold apparatus, as shown in FIG. 1. Additional information on theformation of the parisons can be found in U.S. Pat. No. 2,151,876 andthe patents cited therein.

The two halves of the blank mold 16 are then pivoted open and thesupport arm 20 invert transfers the formed parisons 15, neck ring 18,and neck ring holder 19, to the blow mold apparatus 12, as depicted inFIG. 2. A known transfer mechanism 11 which is suitable for use with thepresent invention is disclosed in U.S. Pat. No. 3,024,571. Basically, itcomprises a pinion 30 and an engaging vertically disposed pinion rack31, both mounted upon a stationary base or section box 32, and operatedby means of a piston and cylinder assembly 33. Compressed air throughone inlet 34 of the cylinder 35, pushes the piston 36 and piston rod 37upward, thereby driving the engaged pinion 30 about its fulcrum shaft 38and invert transferring the support arm 20 and parisons 15 to the blowmold apparatus 12. In order to return the support arm 20 to the blankside, the air in the cylinder 35 is bled, and additional air is fedthrough the inlet 34a to the reverse side 46 of the cylinder 35.

In the present invention, the formed parisons 15 are deliveredalternately to one of two blow mold stations, 50 and 51, of the blowmold apparatus 12. In FIG. 2 the parisons 15 are being delivered to theupper blow mold station 50.

The mold stations, 50 and 51, include, in the form shown, in FIGS. 1 and1a, two multiple cavity cooperating mold sections 52, 52a detachablysupported respectively by mold holder arms 53, 53a and which areopenable and closeable translationly by means of respectivepiston/cylinder assemblies 54, 54a. Each of the piston/cylinderassemblies 54, 54a, includes two cylinder mechanisms 55, 55a and 56,56a, each of which operate one of the two cooperating mold sections 52,52a. For purposes of illustration, one of each of the mechanisms at eachblow mold station, 50 and 51, is shown in sectional view in FIG. 1a.

Each cylinder mechanism, 55, 55a and 56, 56a includes a respectivecylinder 60, a piston 61, a piston rod 62, and two air inlets 63 and 63afor the upper cylinder assembly 55, and 63b, 63c for the lower cylinderassembly 55a. The piston rods 62 are connected to the respective moldholder arms 53, 53a. In each of these sections compressed air isintroduced, through the inlet 63 or 63a, into the cylinder 60 and pushesthe piston 61 and piston rod 62 outward, thereby opening the moldsections 52, as illustrated by the upper blow mold station 50 in FIG.1a. When compressed air is applied through the other inlet 63a or 63b,and the air on the opposite side of the piston 61a is allowed toevacuate, the piston rod 62 or 62a is forced back into the associatedcylinder 60a, thereby closing the mold sections 52 or 52a, as shown bythe lower blow mold station 51 in FIG. 1a. Movement of the piston rodscauses the mold holders arms 53, 53a to move to open and close the moldsections. The mold holder arms and mold sections are caused to movealong a plane that is perpendicular to the longitudinal axis of thebottles formed in the mold sections. Thus, the mold sections movetranslationly away from and towards one another during the opening andclosing of the mold sections. This expedient, combined with the vacuumforce holding the mold closed, greatly reduces the complexity of themold operating mechanism.

Each of the pair of stations, 50 and 51 is supported upon a respectiveplate 64, 64a which is affixed to laterally spaced sliding bars 65, 65aand finally aligned to the stationary base 32 by means of a respectivebracket 66 66a. Bearings 67 affixed to the brackets assure horizontalalignment. The sliding bars 65, 65a and thus the stations 50 and 51, arereciprocated up and down by means of a piston/cylinder assembly 70, fora purpose to be explained below. The piston/cylinder assembly 70includes a cylinder 71, piston 72, piston rod 73, air inlets 74 and 74a,and a drive plate member 75. Compressed air admitted into the cylinder71 through the air inlet 74 pushes the piston 72 and rod 73 upward,thereby resulting in the drive member 75 raising the stations, 50 and51. Compressed air admitted to the other side of the piston 72 throughthe air inlet 74a pushes the piston 72 downward, thereby lowering theblow mold stations, 50 and 51.

The timing of opening and closing the blow mold sections 52 iscontrolled to coincide with the removal of the finished bottles 80 anddelivery of the formed parisons 15, as shown in FIGS. 1 and 2. Removalof the finished bottles 80 is accomplished by means of a conventionaltakeout jaw assembly 81. The takeout jaw assembly 81 includes pairs oftakeout jaws 82 supported by a takeout arm 83 which is pivotally mountedon a bracket 84 (FIG. 2). Thus, finished bottles 80 are removed from theblow mold sections 51 and 52 and delivered to a dead-plate 85 where theyare subsequently transferred to a hot end treatment station (not shown)and an annealing lehr (not shown).

Expansion of the parisons 15 is preferably performed by applying avacuum through slits or apertures (not shown) within the mold sections51 and 52. The vacuum lines may comprise flexible hoses 90 connected tothe hollow interior of each of the sliding bars 65. The vacuum withinthe sliding bars is utilized to expand the parisons 15 in a knownmanner. The valve controlling the vacuum to the mold is located as closeto the mold as possible as is known in the art. Vacuum expansion ispreferred in order to promote uniformity in glass distribution and toassist in holding the mold sections 52 together. However, blow expansionwould also be suitable. Additional information on expanding the parisonsinto bottles can be found in U.S. Pat. No. 1,911,119.

After the finished bottles 80 are removed from the mold sections 52 ofthe upper blow mold station 50 and the formed parisons 15 are deliveredthereto, the piston/cylinder assembly 33 of the transfer mechanism 11 isactuated to return the neck rings 18 to the parison-forming unit 10. Thepiston/cylinder assembly 70 is then actuated to raise the stations, 50and 51. This is shown in FIG. 3. When the lower blow mold station 51reaches the takeout position, the blow mold sections 52 are opened byaction of the piston/cylinder assembly 54, the finished bottles 80 areremoved by the take-out mechanism 81 and the new parisons 15 arepositioned in the mold sections 52, as shown in FIG. 5. The moldsections 52 are immediately closed by the action of the piston/cylinderassembly 54 and then the piston/cylinder assembly 70 is actuated tolower the blow mold stations, 50 and 51, to the position shown in FIG. 1and the process is repeated. Thus, one parison forming unit 10 is usedto supply parisons to mold stations. The mold stations are reciprocatedin a substantially vertical plane to a takeout position where thefinished bottles are removed and another set of parisons supplied to themold station. The mold stations are then reciprocated until the othermold station is in the takeout position and the process is repeated forthat mold station.

The expansion of the parisons 15 in the upper mold station 50 can startat any time after delivery of the parisons, even while the station 50 isin motion. The reheating of the parisons continues to take place duringthe transfer from the parison forming unit and while the parisons are inthe mold stations prior to blowing. Reheating will occur in the moldstations as long as the parisons are not in contact with the walls ofthe mold. A portion of the reheat time in the mold stations will occurwhen the mold stations are in motion. However, since the mold stationsmove in a vertical direction the parisons are not caused to deform orshift off center in the mold stations. In fact, the reheating in themold stations will serve to redistribute any hot glass in the parisonthat has shifted off center due to the forces generated in transferringthe parison forming unit to the mold stations.

The amount of reheating time available is dependent on the length oftime between the point at which the parisons are removed from thecontact with the blank mold and the point at which the parisons arefully expanded in the mold. By utilizing two blow mold stations theparisons can remain in the molds for a longer period of time forreheating without causing the bottle production operation to slow down.The reciprocating cycle of the mold stations, the opening and closing ofthe molds, the blowing of the parison into a bottle and the reheat timealotted in a particular bottle can all be controlled to achieve the bestpossible results.

A timing drum 95 is usually used to control the transfer of the parison,the reciprocation of the mold stations, the opening and closing of themolds, the blowing of the parisons into bottles and the removal of thebottles from the mold stations. An example of suitable timing drumarrangement is shown in U.S. Pat. Nos. 2,084,285 and 2,151,876 althoughit should be noted that almost any mechanical or electrical controldevice can be used to control the bottle forming process. The timingdrum or other control device used are standard components in thisindustry and as such are not part of applicant's invention. The controlof the above functions by the timing drum provides considerableflexibility in selecting the amount of reheat time and consequently blowtime for the bottles that are manufactured. This flexibility isnecessary to allow the machines to manufacture bottles of differentdesigns at maximum production speed for each design.

For example the timing drum 95 may be set up to offset the differenteffects of gravity on the parisons within the two sets of blow molds.When the sets of blow molds 50 moves up from the receiving station theparisons therein will tend to elongate while in the set of blow molds 51that move down from the receiving station the parisons will tend to becompressed.

It should be apparent that, while a preferred embodiment of the presentinvention has been described above in detail, other embodiments ormodifications thereto will be obvious to persons skilled in the artwithout departing from the scope of the invention as defined in thefollowing claims.

What I claim is:
 1. Apparatus for manufacturing glass containerscomprising:first and second blow molds, means for supporting said blowmolds and means for reciprocating said supporting means along asubstantially vertical path to bring said first and second blow moldsinto and out of a receiving position; means for delivering parisons tosaid blow molds when said blow molds are located at said receivingposition; means for expanding the parisons in the blow molds intocontainers when said blow molds are out of said receiving position; andmeans for removing the expanded containers from the blow molds when theblow molds are located at the receiving position.
 2. Apparatus of claim1 wherein the blow mold supporting means includes a sliding barpositioned in a substantially vertical plane.
 3. Apparatus in accordancewith claim 1 in which the parison expanding means is individuallyadjustable in each of the blow mold stations.
 4. Apparatus in accordancewith claim 1 in which said first and second blow molds comprisecooperating half mold sections, and means to open and close said moldsections in a translational movement along a plane perpendicular to thelongitudinal axis of containers formed in said blow molds.